Thyroid gland
=Introduction= Thyroid is excised for dominant or solitary nodules; it is rare in modern times for thyroidectomy to be performed for thyroiditis or for Graves' disease. The questions to be answered include: *Is the nodule solitary or is it part of nodular goiter, i.e., a dominant nodule? *If it is solitary (or one of a small number of nodules), is it a neoplastic lesion? *If it is neoplastic, is it malignant? *If it is malignant, what is the cell derivation and tumor type? *Is it multifocal? *Is there tumor capsule invasion? *Is there vascular invasion? *Is there extension beyond the thyroid? =Fresh Handling= #Weigh the specimen. #Measure the right and left lobes, the isthmus, and the pyramidal lobe if present. #Remove any staples. #Look for attached parathyroid glands; these will be hard to find after inking. Describe location and remember to submit them later. Note: these are only occasionally identifiable grossly. #Ink the gland entirely black. #Small specimens can be dunked in formalin at this point. Large specimens will fix much better if you make a single coronal cut in each lobe, and you will then be able to take a sample for tissue banking. ##If you do open the specimen, describe the size, texture and border of the lesion before banking. ##The entire central portion of the lesion can potentially be banked for research, but a piece 3-10 mm on a side is sufficient. Do not bank the capsule of the lesion. ##Also bank some normal tissue from an uninvolved part of the gland. =Grossing In= #Before handling the tissue, examine the requisition form and/or any history to determine the clinical scenario. In descending order of frequency, this will usually be follicular neoplasm, papillary carcinoma, or multinodular goiter. #Start with one of the lobes, preferably the one containing the main lesion. Make serial sections in the axial plane at 3 mm intervals to identify any focal lesions; describe these. Submit sections according to the clinical scenario, as described below. #Repeat with the other lobe and the isthmus. #In addition to the sections you take to document any lesions, take two sections from the uninvolved part of each lobe and one section from the isthmus. #Any perithyroidal lymph nodes, including any anterior to the isthmus (“Delphian” lymph nodes), should be submitted in toto. As a rule of thumb for sectioning, submit entire gland if it weights 25 grams or less. Follicular neoplasm (Follicular adenoma, rule out carcinoma) Submit the entire capsule of the lesion with a small amount of adjacent thyroid. The center of the lesion does not need to be submitted. Papillary carcinoma #Lesion <3.0 cm: Submit entire lesion #Lesion >3.0 cm: Submit one section per 0.5 cm of lesion. #Make sure to sample the tumor in relationship to the perithyroidal soft tissue. Medullary carcinoma #Lesion <3.0 cm: submit entire lesion and entire remainder of gland #Lesion >3.0 cm: Submit 6-8 blocks of lesion and entire nontumoral thyroid (don't need to submit entire lesion). #If known to be medullary carcinoma, preorder calcitonin and CEA in one tumor block Graves' disease, thyroiditis or nodular goiter #Take one section for every 10 grams of thyroid, up to 100 grams or 10 blocks. Take one section for every additional 20 grams if weight exceeds 100 grams. #For any grossly encapsulated nodules that do not appear to be simply hyperplastic, submit the nodule like you would for a follicular neoplasm (entire capsule and adjacent thyroid submitted). Prophylactic thyroidectomy for familial medullary carcinoma, MEN2 and/or ret germline mutation #The entire gland should be submitted. #Orient sections from upper poles to lower poles and submit isthmus separately. #Calcitonin immunostain should be ordered on all blocks to look for C cell hyperplasia. =Sample Dictation= The specimen is received fresh, labeled with the patient’s name and medical record number, designated “thyroidectomy”, and consists of a total/partial/completion thyroidectomy specimen weighing ___ grams, including right lobe measuring ___ x ___ x ___ cm, left lobe measuring ___ x ___ x ___ cm, and isthmus measuring ___ x ___ x ___ cm. A pyramidal/accessory thyroid lobe measuring ___ x ___ x ___ cm is also recognized. The posterior surface of the thyroid gland shows a single tan-brown ovoid nodule measuring ___ cm, representing a potential parathyroid gland. The specimen has been oriented by the surgeon, with a short suture marking the right superior lobe and a long suture marking the isthmus. The capsule is inked black and the specimen is sectioned to reveal unremarkable red-tan/beefy red/pale tan/black thyroid parenchyma. The right lobe contains a solitary, solid/cystic, round/ovoid/irregular, well/poorly circumscribed nodular lesion measuring ___ x ___ x ___ cm, ___ in color, soft/firm/hard/gelatinous/rubbery/friable in consistency, with a well/poorly defined capsule, with/without focal infiltration of the lesional capsule, with a homogenous/heterogenous, smooth/irregular, fleshy/variegated cut surface, with/without areas of hemorrhage and necrosis, with a central/peripheral fibrotic scar possibly representing the prior FNA site, situated in the superior/inferior pole/ in the interpolar region, ___ cm from the nearest inked capsular surface. Serial sectioning of the remaining gland reveals no other grossly apparent lesions. =Review and Signout= Know why they are taking out the thyroid. If the patient had an FNA diagnosis of "follicular neoplasm", the main differential is follicular adenoma vs. follicular carcinoma (the latter has capsular or vascular invasion by definition). If the FNA diagnosis was “follicular-derived neoplasm”, then the differential includes follicular variant of papillary thyroid carcinoma. If it's for papillary thyroid cancer, then you should find the nodule. If it's a completion lobectomy, then the patient had a thyroid cancer in the other lobe, and they are taking out this lobe to further stage the patient. If it's for goiter or Hashimoto's, often you'll find an incidental papillary microcarcinoma (up to 24% of goiters have them!). If you have a carcinoma (but not if you only have an incidental papillary microcarcinoma, <1 cm), report this using a synoptic. Also use a synoptic for a clinically known (i.e. non incidental) thyroid carcinoma even if <1.0 cm. Sample diagnostic lines: 1. Thyroid, ___ grams, left, partial thyroidectomy: 2. Thyroid, ___ grams, total thyroidectomy: 3. Thyroid, ___ grams, right, completion thyroid lobectomy: :-Multinodular goiter (with mild/moderate/severe chronic lymphocytic thyroiditis). :-Hashimoto's thyroiditis. :-Incidental papillary microcarcinoma, ___ cm, right thyroid. :-Thyroid with hyperplastic nodule, ___ cm, right thyroid. :-Chronic lymphocytic thyroiditis. :-One unreparkable parathyroid gland :-One perithyroidal/intrathyroidal lymph node, no tumor seen (0/1). :-Follicular adenoma, ___ cm, right thyroid. :-Follicular carcinoma, ___ cm, thyroid. :-Papillary thyroid carcinoma, ___ cm, left thyroid. :-Papillary and follicular hyperplasia with stromal diffuse lymphocytosis consistent with the clinical history of Graves’ disease. ---- Return to Endocrine